Support AWS CloudWatch for SQL audit sinking

[mlycore]

Feature Request

Is your feature request related to a problem? Please describe:

n/a

Describe the feature you'd like:

Support AWS CloudWatch for SQL auditing sinking, store the data in log groups of AWS S3

Describe alternatives you've considered:

Using Kinesis, or EventBridge to send the audit data to other systems.

Teachability, Documentation, Adoption, Migration Strategy:

n/a

[mlycore]

Tested AWS CloudWatch in #258 . Since there is a quota for each log stream, this may find another way to handle the logs.

[mlycore]

Try to use EventBridge to transfer audit event logs to CloudWatch. And add SQL digest in the future.

[mlycore]

Using AWS EventBridge as a mpsc AuditChannel, every proxy should sink their SQL audit event to the channel, the AuditServer will consume AuditChannel events and send it to AWS EventBridge.